A031248 a(n)=(# 1's)-(# 2's) in first n terms of A031235.

1, 0, 0, 0, 0, 1, 2, 3, 2, 3, 3, 4, 4, 5, 5, 4, 5, 4, 3, 2, 2, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 2, 3, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 6, 7, 8, 9, 10, 9, 10, 11, 11, 12, 13, 13, 14, 15, 15, 14, 15, 16, 15, 16, 15, 14

Offset

1,7

Links

Table of n, a(n) for n=1..82.

Mathematica

Accumulate[Which[#==1, 1, #==2, -1, True, 0]&/@(Reverse[IntegerDigits[ #, 5]]&/@ Range[ 0, 40]//Flatten)] (* Harvey P. Dale, Aug 02 2016 *)

Crossrefs

Sequence in context: A112212 A102314 A205146 * A030582 A217438 A036762

Adjacent sequences: A031245 A031246 A031247 * A031249 A031250 A031251

Keyword

nonn

Author

Clark Kimberling

Status

approved